1. Technical Field
The present invention relates to a control circuit and a control method which can control at least one of permittivity and permeability. The invention also relates to an impedance adjusting circuit, an impedance automatic adjusting circuit, a radio transceiver circuit, a control method, an impedance adjusting method, an impedance automatic adjusting method, and a radio transceiving method.
2. Related Art
Permittivity and permeability have prescribed physical influences on signals such as an electric signal which flows through a signal path of an electric circuit and a radio signal for radio transmission or reception. For example, permittivity and permeability influence an electric signal in such a manner as to change its amplitude, phase, delay, or the like. For another example, a characteristic of an electric circuit can be controlled by controlling permittivity. In this connection, JP-A-2003-209266 discloses a technique for varying the capacitance of a capacitance component by controlling permittivity.
As described above, permittivity and permeability have prescribed physical influences on an electric signal and a radio signal and change their amplitudes, phases, delays, or the like. That is, if permittivity or permeability can be controlled in a desired manner, a desired influence can be given to a signal such as an electric signal or a radio signal.
In the technique of JP-A-2003-209266, to control the permittivity of a dielectric crystal in a desired manner, it is necessary to not only apply, to the dielectric crystal, light whose energy is equal to the band gap energy of the dielectric crystal but also apply an electric field to the dielectric crystal. This requires a complex configuration and control.